电针调控新西兰兔骨关节炎性疼痛及对脊髓IL-17、IL-17R表达的影响

目的 研究电针是否通过抑制脊髓内白细胞介素(IL)-17及IL-17R的表达来调控新西兰兔骨关节炎性疼痛.方法 新西兰兔随机分为假手术组、炎症模型组、假手术+IL-17组、炎症+抗IL-17组、炎症+电针组、炎症+假电针组,每组8只,4％木瓜蛋白酶构建兔骨关节炎模型,IL-17及IL-17抗血清采用椎管内注射,电针组选择电针刺激足三里(30 min,2 Hz连续波,1～2 mA),假电针组采用非穴位刺激,测定兔痛阈,采用实时荧光定量PCR(RT-qPCR)检测兔脊髓组织IL-17、IL-17R的mRNA表达,Western bolt检测IL-17、IL-17R蛋白表达.结果 在构建骨关节炎模型后新西兰兔痛阈显著下降(P＜0.05),椎管注射IL-17后可以显著降低假手术新西兰兔痛阈(P＜0.05),而椎管注射IL-17抗血清后可明显增加骨关节炎模型兔痛阈值.选择足三里电针刺激可显著提升兔痛阈(P＜0.05).骨关节炎模型组IL-17、IL-17R的mRNA及蛋白表达显著增加(P＜0.05),而电针刺激后其表达显著下降(P＜0.05).结论 新西兰兔骨关节炎性疼痛发生可能涉及脊髓IL-17异常表达,而电针可能通过抑制脊髓IL-17、IL-17R的表达来调控骨关节炎性疼痛.     

三氯乙酸对L-02细胞DNA甲基化转移酶1蛋白及mRNA表达的影响

目的探讨三氯乙酸(TCA)染毒对L-02细胞DNA甲基化转移酶1(DNMT1)蛋白及mRNA表达的影响。方法取处于对数生长期的正常肝细胞(L-02细胞),分别加入含0(对照)、0.1、0.3、0.9 mmo/L TCA的培养液继续培养24、48、72 h,同时,设DNA甲基化酶抑制剂5-氮杂胞苷(5-aza-d C,5μmol/L)处理组,TCA-re组(0.9 mmol/L TCA处理后换正常培养基继续培养24 h)和人肝癌(HepG2)细胞组作为对照。检测细胞DNMT1蛋白和mRNA的表达水平。结果与对照组比较,各浓度TCA染毒组及5-aza-d C处理组、TCA-re组L-02细胞DNMT1 mRNA的表达水平均较低,而HepG2细胞组DNMT1 mRNA的表达水平较高,差异均有统计学意义(P0.05)。与相同剂量TCA染毒24 h比较,各浓度TCA染毒48、72 h后L-02细胞DNMT1 mRNA的表达水平均较低,除0.1、0.9 mmol/L TCA染毒48 h外,差异均有统计学意义(P0.05)。且随着TCA染毒浓度的升高和染毒时间的延长,L-02细胞DNMT1 mRNA的表达水平均呈下降趋势。与0.9 mmol/L TCA染毒组比较,TCA-re组L-02细胞DNMT1 mRNA的表达水平较高,差异有统计学意义(P0.05)。与对照组比较,各浓度TCA染毒组及5-aza-d C处理组L-02细胞DNMT1蛋白的表达水平均较低,除0.1 mmol/L TCA染毒24、48 h及0.3mmol/L TCA染毒24 h外,差异均有统计学意义(P0.05);而TCA-re组L-02细胞和HepG2细胞组DNMT1蛋白的表达水平均无明显变化。与相同剂量TCA染毒24 h比较,各浓度TCA染毒48、72 h后L-02细胞DNMT1蛋白的表达水平均较低,差异均有统计学意义(P0.05)。除TCA染毒24 h时L-02细胞DNMT1蛋白的表达水平随染毒浓度的升高而呈先升高后下降的趋势外,随着TCA染毒浓度的升高和染毒时间的延长,L-02细胞DNMT1蛋白的表达水平均呈下降趋势。与0.9 mmol/L TCA染毒组比较,TCA-re组L-02细胞DNMT1蛋白表达水平较高,差异有统计学意义(P0.05)。结论 TCA体外染毒可能通过抑制DNMT1的表达维持或者促进细胞的DNA低甲基化状态。     

A review of toxicity studies on graphene-based nanomaterials in laboratory animals

We summarized the findings of toxicity studies on graphene-based nanomaterials (GNMs) in laboratory mammals. The inhalation of graphene (GP) and graphene oxide (GO) induced only minimal pulmonary toxicity. Bolus airway exposure to GP and GO caused acute and subacute pulmonary inflammation. Large-sized GO (L-GO) was more toxic than small-sized GO (S-GO). Intratracheally administered GP passed through the air-blood barrier into the blood and intravenous GO distributed mainly in the lungs, liver, and spleen. S-GO and L-GO mainly accumulated in the liver and lungs, respectively. Limited information showed the potential behavioral, reproductive, and developmental toxicity and genotoxicity of GNMs. There are indications that oxidative stress and inflammation may be involved in the toxicity of GNMs. The surface reactivity, size, and dispersion status of GNMs play an important role in the induction of toxicity and biodistribution of GNMs. Although this review paper provides initial information on the potential toxicity of GNMs, data are still very limited, especially when taking into account the many different types of GNMs and their potential modifications. To fill the data gap, further studies should be performed using laboratory mammals exposed using the route and dose anticipated for human exposure scenarios.     

Oral Vancomycin Prophylaxis as Secondary Prevention Against Clostridioides difficile Infection in the Hematopoietic Stem Cell Transplantation and Hematologic Malignancy Population

Clostridioides difficile infection (CDI) is a common complication in the hematopoietic stem cell transplantation (HSCT) and hematologic malignancy (HM) population. CDI is associated with increased hospital length of stay, health care and societal costs, morbidity, and mortality. Identifying strategies for secondary prevention of CDI is of extreme importance in the HSCT/HM population. In this study, our primary objective was to evaluate the effectiveness and safety of an oral vancomycin prophylaxis (OVP) protocol for secondary prevention of CDI in a retrospective cohort of adult autologous/allogeneic HSCT recipients and patients with HM who did not undergo HSCT with a first CDI episode treated with concomitant broad-spectrum antibiotics (BSA). Patients were diagnosed and treated for CDI as inpatients and/or outpatients and were divided into 2 groups based on a preprotocol versus postprotocol analysis: the OVP group, comprising patients who received planned monotherapy with oral vancomycin 125 mg every 6 hours for 14 days for a first episode of CDI and subsequently received OVP posttreatment and a no OVP (NOVP) group, comprising patients who received planned monotherapy with oral vancomycin 125 mg every 6 hours for 14 days for a first episode of CDI and subsequently did not receive OVP posttreatment. OVP was defined as vancomycin 125 mg every 12 hours for up to 7 days after BSA discontinuation. The primary endpoint was recurrent CDI (rCDI), defined as symptoms of loose stools/diarrhea with high clinical suspicion for CDI prompting empiric therapy within 60 days of completion of treatment/prophylaxis for the first CDI episode. The incidence of vancomycin-resistant enterococcal (VRE) infection and 60-day mortality were also compared between the 2 groups. Multivariate logistic regression was created from associated variables to identify independent associations with rCDI. A total of 50 patients were included, 21 in the OVP group (42%) and 29 in the NOVP group (58%). The mean patient age was 58 years, and the cohort was 60% male and 86% Caucasian. HSCT was performed in 60% of the patients, and 76% of CDI cases were diagnosed during hospitalization. The rate of rCDI was significantly lower in the OVP group compared with the NOVP group (5% [1 of 21] versus 35% [10 of 29]; P= .016), with no subsequent increase in VRE infection rate (14% [3 of 21] versus 10% [3 of 29]; P = .686). By multivariable logistic regression, rCDI was inversely associated with OVP (odds ratio [OR], .14; 95% confidence interval [CI], .007 to .994; P = .049) and directly associated with outpatient CDI diagnosis (OR, 8.72; 95% CI, 1.816 to 49.158; P = .007). No between-group differences were found in 60-day mortality (10% [2 of 21] for OVP versus 7% [2 of 29] for NOVP; P > 0.999). OVP appears to be safe and effective for secondary prevention of CDI in the HSCT/HM population. Prospective trials are needed to validate the effectiveness of OVP in this vulnerable population to prevent rCDI.     

Cell-cycle-dependent changes in membrane potential of L-929 cells caused by the effect of hydrogen peroxide

 The changes in membrane potential of L-929 fibroblasts caused by H₂O₂ (10–50 μM) at different phases of the cell cycle were investigated. The membrane potential of cells in G0, early G1, and G2/M responded to H₂O₂ by hyperpolarizing, while cells in late G1/S responded by depolarizing. Quinidine (50 μM), a blocker of Ca²⁺-dependent K⁺ conductance, inhibited the hyperpolarization response of L-929 cells to H₂O₂ in all cases. Measurements of reactive oxygen species (ROS) production by the cells at the same cell cycle phases indicated that the hyperpolarization response of the cells is linked with minimal production of ROS, and that the depolarization response is associated with maximal production of ROS inside the cell. Received: 5 February 1999 / Received after revision and accepted: 3 March 1999     

Effects of the substituted (S)-3-phenylpiperidine (−)-OSU6162 on PET measurements in subhuman primates: Evidence for tone-dependent normalization of striatal dopaminergic activity

(−)-OSU6162 is a substituted (S)-3-phenylpiperidine derivative which exhibits some affinity to the dopamine D₂ receptor family. In vivo, the compound displays a unique normalizing profile on psychomotor activity by an intriguing mixture of stimulatory and inhibitory properties. In the present investigation, some of the effects of (−)-OSU6162 on central dopaminergic function were studied by positron emission tomography (PET) and L-[¹¹C]DOPA in anaesthetized female rhesus monkeys. (−)-OSU6162 displayed a dopaminergic tone-dependent effect with a reduction in the striatal L-[¹¹C]DOPA influx rate in monkeys with high baseline values and an increased striatal L-[¹¹C]DOPA influx rate in animals with low baseline values. Infusion of (−)-OSU6162 for a whole day resulted in a stable effect with no evidence of tolerance. (−)-OSU6162 also stabilized dopaminergic function by attenuating the upregulation of the striatal L-[¹¹C]DOPA influx rate which has previously been shown to occur following 6R-BH₄ or 6R-BH₄ + L-tyrosine infusions. This “Protean” effect of (−)-OSU6162 on the striatal dopaminergic function corresponds to previous behavioral observations in intact animals and demonstrates a true functional correlation to the measures obtained with L-[¹¹C]DOPA and PET. The normalizing and stabilizing profile of (−)-OSU6162 should be of value in treating a variety of disorders where an underlying dysregulation or disruption of dopaminergic function can be assumed. Synapse 28:280–287, 1998. © 1998 Wiley-Liss, Inc.     

L-DOPA modulates striatal dopaminergic function in vivo: Evidence from PET investigations in nonhuman primates

Significant increases in striatal L-[¹¹C]DOPA retention were observed in adult female rhesus monkeys with positron emission tomography (PET) following administration of drugs that increase cerebral L-DOPA concentrations. The monkeys were scanned twice: at baseline (using 10–50 μg of tracer substance) and during continuous administration of L-DOPA (3 or 15 mg/kg/h) and 6-R-Erythro-4,5,6,7-tetrahydrobiopterin (6R-BH₄) (5 mg/kg/h) and during combined administration of both drugs. PET scans of L-[¹¹C]DOPA distribution were obtained in GE2048-15B or GE4096-15WB Plus positron tomographs. In all studies the specific striatal L-[¹¹C]DOPA influx rate increased by an average of 17–20%. These increases were significantly higher than the retest variability obtained with saline infusions under identical experimental conditions. In individual monkeys the magnitude of increase in the striatal L-[¹¹C]DOPA influx rate varied from no effect of the drug infusion to a 45% increase. Taken together, the results of this study demonstrate that L-DOPA in itself can affect dopaminergic neurotransmission in vivo and also adds further evidence that the neuromodulatory effects of the amino acid are predominantly autoreceptor antagonist-like. The findings most likely have importance for the further understanding of the dopaminergic system in neurodegenerative and psychiatric disorders. Synapse 25:56–61, 1997. © 1997 Wiley-Liss, Inc.     

Differential expression of voltage-gated Ca2+ conductances in human neuroblastoma NB69 cells cultured in defined serum-free and astrocyte-conditioned media

Voltage-gated Ca²⁺ conductances were investigated with the whole-cell patch-clamp technique-either using Ca²⁺ or Ba²⁺ as charge carriers-in NB69 human neuroblastoma cells plated in “defined” serum-free (DM) and in “astroglial-conditioned” media (CM). Cells expressed the microtubule associated protein 1A when plated in both media, indicating neuronlike differentiation. Cells of similar sizes and shapes were selected for recordings. Different sets of voltage-gated Ca²⁺ current types were usually expressed in DM- and CM-plated cells. DM-plated cells exhibited a high-voltage-activated current (HVAC) in isolation, whereas 43% of the CM-plated cells also displayed the low-voltage-activated current (LVAC). The membrane surface density of the HVAC was about twofold higher in CM than in DM-plated cells and increased with plating time from 10 and 16pA/pF (days 1-4) to 24 and 37pA/pF (days 5-10) in DM- and CM-plated cells, respectively. However, the amplitude of the LVAC did not change significantly with culture age. In conclusion, NB69 cells expressed HVAC in isolation when plated in DM, whereas both HVAC and LVAC were present in many CM-plated cells, suggesting that the CM contained diffusible factors secreted by astroglial cells which: (1) could induce the appearance of the LVAC and (2) increased HVAC current expression. GLIA 20:70-78, 1997. © 1997 Wiley-Liss, Inc.     

L-15N亮氨酸和质谱测定大鼠肝蛋白质合成

目的:建立稳定同位素L-15N亮氨酸测定大鼠肝蛋白质合成率的方法.方法:分别测定静脉注射相同剂量L-15N亮氨酸不同时相的大鼠肝15N丰度及不同剂量L-15N亮氨酸同一时相的大鼠肝15N丰度.结果:大鼠肝游离氨基酸池中15N同位素丰度在注射后30 min内呈线性上升并达高峰,维持4 h后缓慢下降,肝蛋白质中的15N丰度30 min至12 h基本维持不变;随着注射剂量的增加,大鼠肝蛋白质分数合成率亦增加,当L-15N亮氨酸剂量＞1.0 mmol/kg,分数合成率并不随施加L-15N亮氨酸剂量的加大而增加.结论:在进行大鼠肝蛋白质合成率测定时,一次性静脉注射的测量最佳时限为30 min,剂量为1.0 mmol/kg.     

Past, present and future of A(2A) adenosine receptor antagonists in the therapy of Parkinson's disease

Several selective antagonists for adenosine A_2A receptors (A_2AR) are currently under evaluation in clinical trials (phases I to III) to treat Parkinson's disease, and they will probably soon reach the market. The usefulness of these antagonists has been deduced from studies demonstrating functional interactions between dopamine D₂ and adenosine A_2A receptors in the basal ganglia. At present it is believed that A_2AR antagonists can be used in combination with the dopamine precursor L-DOPA to minimize the motor symptoms of Parkinson's patients. However, a considerable body of data indicates that in addition to ameliorating motor symptoms, adenosine A_2AR antagonists may also prevent neurodegeneration. Despite these promising indications, one further issue must be considered in order to develop fully optimized antiparkinsonian drug therapy, namely the existence of (hetero)dimers/oligomers of G protein-coupled receptors, a topic that is currently the focus of intense debate within the scientific community. Dopamine D₂ receptors (D₂Rs) expressed in the striatum are known to form heteromers with A_2A adenosine receptors. Thus, the development of heteromer-specific A_2A receptor antagonists represents a promising strategy for the identification of more selective and safer drugs.